A Covid-19 vaccine being developed by AstraZeneca and the University of Oxford going under Phase 3 study has been put on hold due to a suspected serious adverse reaction in a participant in the United Kingdom on Tuesday.
According to a spokesperson, “As part of the ongoing randomized, controlled global trials of the Oxford coronavirus vaccine, our standard review process was triggered and we voluntarily paused vaccination to allow the review of safety data by an independent committee. This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials.”
They also mentioned that in large trials, illnesses will sometimes happen by chance but it must be reviewed independently and immediately as they are committed to the safety of their participants and the highest standards of conduct in their trials.
However, the spokesperson also added that they are working to expedite the review of the single event to minimise any potential impact on the trial timeline. But it was not immediately clear where the patient was, or the nature and severity of their illness.
AstraZeneca’s U.S. trials which began its Phase 3 trial in late August is currently taking place at 62 sites across the country, according to a government registry, though some have not yet started enrolling participants. Phase 2/3 trials were started in the U.K., Brazil, and South Africa previously. The company started enrolling 30,000 volunteers across all these sites on August 31.
The vaccine is called AZD1222 and it uses a weakened version of a common cold-causing adenovirus that has been engineered to code for the spike protein that the novel coronavirus uses to invade cells. After vaccination, this protein is produced inside the human body, which primes the immune system to attack the coronavirus if the person is later infected with.